The IAR.80 first flew in 1938 and entered service in 1941 with the Romanian Air Force. Industria Aeronautica Romana (IAR) was a government-subsidised company and won the bid to produce Romania's newest fighter. It was an advanced design at the time, and very close in ability to the early Messerschmitts and Spitfires, but by 1944 it was outdated.

The IAR.80 had only 4 x 7.92mm machine guns due to supply problems, but this was addressed with next version.

The IAR.80A had 6 x 7.92mm machine guns and a more powerful engine.

The IAR.80B had 13.2mm machine guns and provision to carry a bomb or drop tank.

There were several more variants - 81, 81A, 81C, 80M, which were designed as dive bombers or general strike aircraft, some of which were converted back to pure fighters before delivery.

Even armed with 2 x 20mm cannon and 4 machine guns, the IAR.80 still had difficulty shooting down US B-24s, so a later addition to the armament included the German Wfr.Gr.21rocket under each wing.